extras: Some refactorings

* Move ast package one level up
* Unexport most types
* Simplify config

extras/ast.go

@@ -0,0 +1,108 @@
+package extras
+
+import (
+	"github.com/yuin/goldmark/ast"
+)
+
+type inlineTagType int
+
+const (
+	superscript inlineTagType = iota + 1
+	subscript
+	insert
+	mark
+)
+
+type inlineTag struct {
+	TagType           inlineTagType
+	Char              byte
+	Number            int
+	Html              string
+	WhitespaceAllowed bool
+	ParsePriority     int
+	RenderPriority    int
+}
+
+var superscriptTag = inlineTag{
+	TagType:           superscript,
+	Char:              '^',
+	Number:            1,
+	Html:              "sup",
+	WhitespaceAllowed: false,
+	ParsePriority:     600,
+	RenderPriority:    600,
+}
+
+var subscriptTag = inlineTag{
+	TagType:           subscript,
+	Char:              '~',
+	Number:            1,
+	Html:              "sub",
+	WhitespaceAllowed: false,
+	ParsePriority:     602,
+	RenderPriority:    602,
+}
+
+var insertTag = inlineTag{
+	TagType:           insert,
+	Char:              '+',
+	Number:            2,
+	Html:              "ins",
+	WhitespaceAllowed: true,
+	ParsePriority:     501,
+	RenderPriority:    501,
+}
+
+var markTag = inlineTag{
+	TagType:           mark,
+	Char:              '=',
+	Number:            2,
+	Html:              "mark",
+	WhitespaceAllowed: true,
+	ParsePriority:     550,
+	RenderPriority:    550,
+}
+
+type inlineTagNode struct {
+	ast.BaseInline
+
+	inlineTag
+}
+
+func newInlineTag(tag inlineTag) *inlineTagNode {
+	return &inlineTagNode{
+		BaseInline: ast.BaseInline{},
+
+		inlineTag: tag,
+	}
+}
+
+var (
+	kindSuperscript = ast.NewNodeKind("Superscript")
+	kindSubscript   = ast.NewNodeKind("Subscript")
+	kindInsert      = ast.NewNodeKind("Insert")
+	kindMark        = ast.NewNodeKind("Mark")
+)
+
+func newInlineTagNodeKind(tag inlineTagType) ast.NodeKind {
+	var kind ast.NodeKind
+	switch tag {
+	case superscript:
+		kind = kindSuperscript
+	case subscript:
+		kind = kindSubscript
+	case insert:
+		kind = kindInsert
+	case mark:
+		kind = kindMark
+	}
+	return kind
+}
+
+func (n *inlineTagNode) Kind() ast.NodeKind {
+	return newInlineTagNodeKind(n.TagType)
+}
+
+func (n *inlineTagNode) Dump(source []byte, level int) {
+	ast.DumpHelper(n, source, level, nil, nil)
+}